JPS6023950Y2 - Ferrite core for rotary transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary transformer for a video tape recorder, and relates to an improvement in the direction in which an annular groove is formed in the core of the rotary transformer.

A rotary transformer used as a signal transmission means between the rotary head and the circuit system of a conventional video tape recorder has a disk-shaped ferrite core 1 with a through hole in the center, as shown in FIGS. 1a and 1b, for example. A plurality of concentric annular grooves 2 are formed into a pair, and a winding 4 is placed inside the annular groove 2.
It has been used loaded with.

By the way, ferrite cores come in various shapes, but generally, the desired shape is achieved by powder molding, including the case of the conventional ferrite core for rotary transformers mentioned above, which has a groove shape (concave part). In the case of molding ferrite powder, in consideration of the punching process after the pressing process of the mold used, the side wall 3 of the annular groove 2 is shaped in the punching direction as shown in FIGS. 1a and b.
It is necessary to provide a tapered portion corresponding to t, which causes a loss in terms of the space factor of the winding 4, the shape of the transformer, efficiency, etc., which causes problems.

The purpose of this application is to solve the above problems and provide a ferrite core for a rotor lance that is compact, has high mechanical and electromagnetic precision, and is relatively inexpensive. For a rotary transformer in which a plurality of concentric annular grooves are formed on one side of a flat surface of a disk-shaped ferrite core having holes, and a plurality of signals are transmitted from a plurality of rotating heads corresponding to the annular grooves to a rotating device. In the ferrite core, at least a part of the circumferential side wall from the bottom of the annular groove to the flat surface is formed in a circumference such that the direction in which at least a part of the circumferential side wall is formed is perpendicular to S with respect to the flat surface of the disc-shaped ferrite core. The present invention relates to a ferrite core for a rotary transformer of a video tape recorder, characterized in that a grinding surface is formed parallel to the rotation axis and an annular groove into which a winding can be inserted is provided.

The ferrite core for a rotary transformer of the present application will be explained below with reference to the drawings.

FIGS. 2a and 2b show a side sectional view and a plan view, respectively, of an embodiment of a ferrite core for a rotary transformer according to the present application.

The structural features of the present application are as shown in Fig. 2 a and b and the conventional Fig. 1 a.
As is clear from comparing Figures 2a and 2b, the ferrite core IA is formed on one side of a disc-shaped ferrite core IA with a through hole in the center and a winding pull-out groove (not shown). For example, a ring-shaped grindstone was used to make the side walls 3A of the plurality of concentric annular grooves 2A perpendicular to the plane of the disk-shaped ferrite core IA until they reached the bottom of the annular grooves 2A. This is done by using a grinding means to make the shape stronger.

As mentioned above, the ferrite core for a rotary transformer of the present application is a donut-shaped disc ferrite core that has been pre-formed with a through hole in the center, and one surface of the so-called flat surface side is used for multiple concentric transformer coils. An annular groove 2A is formed.

When a plurality of signals are transmitted from a plurality of rotary heads to a rotary device in correspondence with the annular grooves using a coil made of winding 4A, a rotary transformer is formed to transmit the signals of the rotary head to the stator side.

In this transformer, the forming direction of the side wall 3A of the annular groove 2A of the ferrite core, which is at least part of the circumference from the bottom of the annular groove 2A to the flat surface, preferably the entire circumference, is A circumferential ground surface that is S' perpendicular to the flat surface of the plate-shaped ferrite core IA, that is, a plane, is formed parallel to S' to the rotation axis using a ring-shaped grindstone or the like (not shown).

This circumferentially ground surface was able to provide an annular groove 2A into which the winding wire 4A could be inserted deep and with a high space factor.In particular, the rotary transformer of a handheld video tape recorder has a diameter and thickness. An extremely compact product can be obtained.

As mentioned above, in order to form a small rotary transformer, in addition to improving the magnetic material itself, the shape of the annular groove 2A of the ferrite core made of a circumferentially ground surface plays a decisive role as described above. The inventors discovered this.

Moreover, transmitting video image signals through multiple rotary heads rather than a single groove is an important requirement for reducing the recording tape width and the size of the rotary heads.
Problem □ could not be solved by simply providing concentric grooves, but the present application has made it possible.

As described above, in the ferrite core IA of the present application, the side wall 3A of the shaped annular groove 2A is perpendicular to the plane of the disk, so there is no need for a so-called tapered part, and there is no waste inside the annular groove 2A. The space factor of the winding 4A loaded inside the annular groove 2A is improved, and an extremely compact and highly efficient ferrite core for a rotary transformer for a video device can be obtained.

As mentioned above, when forming the annular groove, if a grinding method using a ring-shaped grindstone is used on the sintered ferrite core, it is relatively inexpensive and the precision of the shaping method is improved, and the electromagnetic characteristics are also less likely to vary. This is an extremely practical idea as it allows for a stable product to be obtained.

[Brief explanation of the drawing]

FIG. 1a is a side sectional view of an embodiment of a conventional ferrite core for a rotary transformer, FIG. 1 is a plan view thereof, and FIG. 2a is a side sectional view of an embodiment of a ferrite core for a rotary transformer of the present application , FIG. 2 shows the same plan view, respectively. 1, IA... Disc-shaped ferrite core, 2, 2
A: Annular groove, 3, 3A: Side wall of annular groove, 4° 4A: Winding wire.

Claims (1)

[Scope of utility model registration request] A plurality of concentric annular grooves are formed on one side of a flat surface of a disk-shaped ferrite core having a through hole in the center, and a plurality of signals are transmitted from a plurality of rotating heads corresponding to the annular grooves to a rotating device. In the ferrite core for a rotary transformer, the direction in which at least a portion of the circumferential side wall from the bottom of the annular groove to the flat surface is formed is perpendicular to S with respect to the flat surface of the disc-shaped ferrite core. This video is characterized in that a circumferentially ground surface is formed parallel to the rotating shaft S and an annular groove is provided in which a plurality of windings can be inserted into a disc-shaped ferrite core at a predetermined space factor. Ferrite core for rotary transformer of tape recorder.